Is it normal for sex to make me sick during pregnancy?

No: I have not heard this complaint before. I would guess that the pressure of the uterus along with pressure from having sex is causing your stomach to get squeezed and that this may make you feel sick. Try another position, like with you one your side.

No. It depends....: ...What you mean by "sick." check with your obstetrician. Perhaps diet or change of position might help.